MIMO signal generator with frequency multiplexing

Abstract

A MIMO signal generator is adapted to generate a MIMO signal is provided. The MIMO signal generator comprises a signal generator, a signal divider and a frequency shifter. The signal generator is adapted to generate a plurality of frequency shifted partial MIMO signals within a first signal generator output signal. The frequency shifted partial MIMO signals being arranged on the frequency axis in a non-overlapping manner. The signal divider is adapted to divide the first signal generator output signal into a plurality of signal paths. The frequency shifter preferably comprises a frequency shifting device in at least one of the plurality of signal paths. The frequency shifting devices are adapted to shift the frequencies of the plurality of frequency shifted partial MIMO signals to a joint carrier frequency, resulting in a plurality of partial MIMO signals, forming the MIMO signal.

What is claimed is: 
     
       1. A MIMO signal generator, adapted to generate a MIMO signal, comprising:
 a signal generator, a signal divider, and a frequency shifter, 
 wherein the signal generator is adapted to generate a plurality of frequency shifted partial MIMO signals within a first signal generator output signal, the plurality of frequency shifted partial MIMO signals being arranged on a frequency axis in a non-overlapping manner, 
 wherein the signal divider is adapted to divide the first signal generator output signal onto a plurality of signal paths, 
 wherein the frequency shifter is adapted to shift frequencies of the plurality of frequency shifted partial MIMO signals to a joint carrier frequency, resulting in a plurality of partial MIMO signals, forming the MIMO signal, and 
 wherein the signal generator is adapted arrange the plurality of frequency shifted partial MIMO signals on the frequency axis in the non-overlapping manner, by placing a carrier frequency of all but one of the plurality of frequency shifted partial MIMO signals to different frequencies. 
 
     
     
       2. The MIMO signal generator of  claim 1 ,
 wherein the frequency shifter comprises a frequency shifting device in at least one of the plurality of signals paths. 
 
     
     
       3. The MIMO signal generator of  claim 1 ,
 wherein the different frequencies are spaced apart at least by a bandwidth of the MIMO signal, or 
 wherein the different frequencies are spaced apart at least by 110% of a bandwidth of the MIMO signal by 120% of the bandwidth of the MIMO signal. 
 
     
     
       4. The MIMO signal generator of  claim 1 ,
 wherein each signal path additionally comprises an antenna for transmitting a partial MIMO signal over the air. 
 
     
     
       5. The MIMO signal generator of  claim 1 ,
 wherein at least one signal path additionally comprises a first filter arranged between the signal divider and the frequency shifting device, adapted to remove signals outside of a frequency shifted bandwidth of the at least one signal path. 
 
     
     
       6. The MIMO signal generator of  claim 5 ,
 wherein at least one signal path additionally comprises a second filter arranged between the frequency shifting device and an output of the at least one signal path, adapted to remove signals outside of the bandwidth of the MIMO signal. 
 
     
     
       7. The MIMO signal generator of  claim 1 ,
 wherein the frequency shifting device is a mixer. 
 
     
     
       8. The MIMO signal generator of  claim 7 ,
 wherein the mixers are connected to common reference frequency means. 
 
     
     
       9. The MIMO signal generator of  claim 1 ,
 wherein the plurality of frequency shifted partial MIMO signals comprises N frequency shifted partial MIMO signals, 
 wherein the signal divider is adapted to divide the first signal generator output signal onto N signal paths, 
 wherein the MIMO signal generator comprises a further signal generator, adapted to generate M frequency shifted partial MIMO signals within a second signal generator output signal, the M frequency shifted partial MIMO signals being arranged on the frequency axis in the non-overlapping manner, 
 wherein the signal divider is adapted to divide the second signal generator output signal in M signal paths. 
 
     
     
       10. The MIMO signal generator of  claim 1 ,
 wherein the signal divider is arranged in a first housing, and 
 wherein the frequency shifter is arranged in a second housing. 
 
     
     
       11. An apparatus comprising a MIMO signal generator according to  claim 1 ,
 wherein the apparatus is a mobile station or a basestation or measuring device. 
 
     
     
       12. A measuring system, comprising a MIMO signal generator according to  claim 1 , and a device under test,
 wherein the device under test comprises a MIMO signal receiver, 
 wherein the MIMO signal generator is adapted to provide the MIMO signal to the device under test, and 
 wherein the device under test is adapted to receive the MIMO signal using the MIMO signal receiver. 
 
     
     
       13. The measuring system of  claim 12 ,
 wherein the MIMO signal receiver is adapted to receive different data streams of a same frequency using separate antennas. 
 
     
     
       14. The measuring system of  claim 12 ,
 wherein the MIMO signal generator comprises an antenna for each signal path, and 
 wherein the MIMO signal generator is adapted to transmit the MIMO signal to the device under test over the air using the antennas of the signal paths. 
 
     
     
       15. The measuring system of  claim 13 ,
 wherein the measuring system comprises an anechoic measuring chamber, and 
 wherein the device under test and at least the antennas of the signals paths are arranged within the anechoic measuring chamber. 
 
     
     
       16. A method for generating a MIMO signal, comprising:
 generating a plurality of frequency shifted partial MIMO signals within a first signal generator output signal, the plurality of frequency shifted partial MIMO signals being arranged on a frequency axis in a non-overlapping manner, 
 dividing the first signal generator output signal onto a plurality of signal paths, 
 shifting the frequencies of the plurality of frequency shifted partial MIMO signals to a joint carrier frequency, resulting in a plurality of partial MIMO signals, forming the MIMO signal, 
 wherein the plurality of frequency shifted partial MIMO signals are arranged on the frequency axis in the non-overlapping manner, by placing a carrier frequency of all but one of the plurality of frequency shifted partial MIMO signals to different frequencies.